Manufacture of regenerated cellulose



rates Pate MANUFACTURE .OF REGENERATED CELLULOSE No Drawing. ApplicationJanuary 30, "1956 Serial No."562,352

l Clairns. (Cl. 106-465) This invention relates to new and usefulimprovements in the manufacture of regenerated cellulose from viscoseinto such articles as continuous filament tire yarn, textile yarn staplefibre, cellophane or sausage casings and the like, and particularlyseems to provide a novel process in which the physical characteristicsof the articles -produced thereby are markedly superior .to thoseobtained through the practice of previous processes.

In the production of viscose threads, cellulose, usually in the form ofhighly-refined dissolving wood pulp, is converted into alkali celluloseby treatment with caustic soda solution. The alkali cellulose so formed,after ageing, is converted into sodium cellulose xanthate by reactionwith carbon disulphide. The sodium cellulose xanthate is dissolved inweak caustic soda solution to form the viscose solution. The viscose isthen filtered, aged, and extruded through fine holes of a spinneretteinto a spinning bath which normally consists of sulphuric acid and saltssuch as sodium sulphate and zinc sulphate. In the production of viscosethreads for tire yarn the filaments thus formed are stretched in aplasticizing bath and are then treated with purifying solution, which insome cases may simply be hot water, and then are treated with a finishor sizing solution, and then are dried and wound into suitable packages.

We have now found that, under certain conditions of coagulation andregeneration of the viscose filaments in the spinning bath, asubstantial difference in cross-sections and marked improvement in thephysical properties of the yarn so formed can be achieved if there ispresent in the viscose in suflicient quantity one or more derivatives ofethylene oxide and aliphatic tertiary-alkyl primary amines. Suchproducts have the generic formula:

where n is an integer between 4 and 50.

One such product which has been found satisfactory in the practice ofthis invention is Priminox as presently manufactured by Rohm & Haas Co.

Benefits will be conferred by 4 to 50 ethylene oxide units in theethenoxy portion of these amide condensation products, but best resultsare obtained with to 30 ethylene oxide units.

In accomplishing the objects of this invention we have found that it isnecessary to incorporate in the viscose at least 1% by weight on thecellulose content of the viscose, and preferably 2% should be used. Nofurther advantage can be obtained by using more than 4%.

The following examples will illustrate preferred embodiments of thisinvention, but the invention must not be construed as limited solely tothese examples:

EXAMPLE 1 Two percent, by weight based on the cellulose content of theviscose (oven dry basis), of derivatives of ethylene oxide and aliphatictertiary-alkyl primary amines known commercially under the trademarkPriminox were added to viscoses and spun "into tire yarnunder theconditions given below. In each .caseaddition was made to the mixingsolution before the .xanthate was dissolved therein. where n, the number:of moles .of ethylene :oxide :in the In one lease the additive *wasfPriminox =43" molecule, was equal to 1. In another case the additivewas "Priminox 32 where n, the number of moles of ethylene oxidein'themolecule, was-equalrto 25. .Acomparative untreated batch .of viscose.was :also made rand spun under identical conditions to the batchescontaining the additives.

Spinning conditions: Viscose composition 7% cellulose-6% .{NaQ Ripeningindex, Hottenroth v30.

'Ripening-index, salt vtest 510.0.

Viscosity, ball fall 60-70 poises. Spinning speed 50 metres/minute.Denier 1'650'(72O'filaments). Immersion of acid bath '28 inches.

Temperature .of acid tbath 60 :C. Acid bath.composition H2804 g./l. ZnSO122.7 g./l. Density, 20 C 1.274.

Percent stretch in second bath The yarn so produced as twisted into a 2ply cord of It can be seen that the batch containing the additivePriminox 43 where the number of moles of ethylene oxide in the additivemolecule was only one, was actually inferior in cord properties to thecontrol batch containing no additive whereas the batch containing theadditive Priminox 32 where the number of moles of 'ethylene oxide in theadditive molecule was 25 gave cord properties markedly superior to thecontrol batch containing no additive. Furthermore, the cross-sections ofthe yarn produced from the batch containing Priminox 32 were markedlydifferent from those produced from the control batch.

The products may be added at almost any stage of the viscose process andeven to the raw material cellulose itself if desired. However, for theaccomplished purpose of the object of this invention we have found thataddition to the mixing solution (the weak caustic soda solution used todissolve the xanthate) before dissolution of the xanthate therein is thesimplest and most eificient method.

Many variations of this process will suggest themselves .to thoseskilled in the art, but such variations are considered as falling withinthe scope of this invention, provided the products employed are withinthe class described.

We claim:

1. In the manufacture of regenerated cellulose by the viscose process,the step of incorporating in the viscose from about 1% to about 4%,based on the weight of celluose in the viscose, of derivatives ofethylene oxide 3 and aliphatic tertiary-alkyl primary amines having thegeneric formula where n is an integer between 4 and 50.

2. The method of claim 1 in which the amount of derivatives of ethyleneoxide and aliphatic tertiary-alkyl primary amines is about 1% based onthe cellulose in the viscose.

3. The method of claim 1 in which the amount of derivatives of ethyleneoxide and aliphatic tertiary-alkyl primary amines is about 2% based onthe cellulose in the viscose.

4. The method of claim 1 in which n is 25.

5. In the manufacture of regenerated cellulose by the viscose process,the step of spinning viscose in the presence of from about 1% to about4%, based on the weight of cellulose in viscose, of derivatives ofethylene oxide and aliphatic tertiary-alkyl primary amines having thegeneric formula where n is an integer between 4 and 50.

6. The method of claim 5 in which the amount of derivatives of ethyleneoxide and aliphatic tertiary-alkyl where n is an integer between 4 and50.

9. The method of claim 5 in which the amount of derivatives of ethyleneoxide and aliphatic tertiary-alkyl primary amines is about 2% based oncellulose in viscose and in which n is 25.

10. The method of claim 1 in which n is an integer between 10 and 30.

References Cited in the file of this patent UNITED STATES PATENTS2,535,044 Cox Dec. 26, 1950 2,593,466 MacLaurin et a1. Apr. 22, 19522,710,861 Charles et a]. June 14, 1955

1. IN THE MANUFACTURE OF REGENERATED CELLULOSE BY THE VISCOSE PROCESS,THE STEPS OF INCORPORATING IN THE VISCOSE FROM ABOUT 1% TO ABOUT 4%,BASED ON THE WEIGHT OF CELLUOSE IN THE VISCOSE, OF DERIVATIVES OFETHYLENE OXIDE AND ALIPHATIC TERTIARY-ALKYL PRIMARY AMINES HAVING THEGENERIC FORMULA